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Clothes Dryer Receptacle Question

Can someone please give me an idea when the Clothes Dryer receptacles were first required by the NEC to be on a 4 conductor branch circuit ?

I inspected a brand new house today in a rural county I've never been in before with a 3 conductor dryer receptacle. Yes, I know it can take time for the NEC to trickle down but it seems to me 4 conductor dryer receptacles have been around awhile. I'm under the impression that any new dryer on the market today would have a 4 prong plug. Kinda leaves my clients in a bind right out of the gate trying to get their new dryer hooked up. I'm going to write it up and wanted to check my gut suspicion.

Re: Clothes Dryer Receptacle Question

Originally Posted by Robert Foster

C
I inspected a brand new house today in a rural county I've never been in before with a 3 conductor dryer receptacle. Yes, I know it can take time for the NEC to trickle down but it seems to me 4 conductor dryer receptacles have been around awhile. I'm under the impression that any new dryer on the market today would have a 4 prong plug. Kinda leaves my clients in a bind right out of the gate trying to get their new dryer hooked up. I'm going to write it up and wanted to check my gut suspicion.

The requirement has been around for so long that the rural county would need to have no electrical code for a new 3-wire dryer receptacle installation to be compliant.

Re: Clothes Dryer Receptacle Question

From what I was told the requirement came about because of the use of digital displays and computer boards. They use 120v circuits so they need to have the proper ground and neutral just like any other 120v circuit. If your using a less advanced dryer then it might not be such a big deal but would be recommended because you never know what the next dryer will be.

Re: Clothes Dryer Receptacle Question

Originally Posted by Robert Ernst

From what I was told the requirement came about because of the use of digital displays and computer boards. They use 120v circuits so they need to have the proper ground and neutral just like any other 120v circuit. If your using a less advanced dryer then it might not be such a big deal but would be recommended because you never know what the next dryer will be.

You were told wrong. The use of the neutral to ground the frame of dryers and ranges was one of a a couple of glaring exceptions to standard grounding procedures used in the rest of the electrical industry. A common issue with the setup is that a new service would be installed leaving the old panel as a sub panel (non-service equipment) and the rules changed, requiring the ground to be present and it often wasn't installed. A lot of range and dryer circuits were run with type SE cable from the original panels and with a new service now feeding the original panel the bare neutral was no longer permitted, also not fixed most times. The main reason for the requirement of a separate ground is that with the frame tied to the neutral, failure of a neutral connection put voltage on the appliance frame. This got real interesting with a properly grounded washer right next to a dryer and the touching that goes on handling damp clothes and transferring them between the two appliances (sometimes adding several more levels to the term "hot" woman). Imagine a dryer with voltage on the frame, someone in bare feet on a slightly damp concrete floor loading/unloading...........

Dryers and ranges used 120 volts for things like motors, low heat settings, timers, and clocks long before digital "stuff" was a concern. I have seen digital equipment on appliances that appears to malfunction when the combination neutral/ground carries current. I'd be very surprised if the NEC even considered poorly designed digital controls as a reason for updating the grounding requirements back in the 90s. Wouldn't surprise me a bit now.

I haven't done the research but one story appears to be that the rules were changed to allow the neutral to serve as the ground for dryers and ranges as a material saving strategy for the WW II era and never changed back. In any event I would have expected the grounding for these appliances to have been brought in line with all other resi grounding requirements when they were imposed and it wasn't.

Occam's eraser: The philosophical principle that even the simplest solution is bound to have something wrong with it.

Re: Clothes Dryer Receptacle Question

IMHO the best you can do is recommend review by a licensed pro. If the NEC trickle down time frame isn't bad enough, the AHJ has the authority to not accept portions of the NEC and/or to accept alternate methods. Ultimately, I believe the installing electrical contractor will be replacing that receptacle at their expense, but the wheels of justice can be glacially slow.

Re: Clothes Dryer Receptacle Question

So is the concensus of the BOARD that if a home has 3-wire rather than 4-wire, then we as inspectors should be writing that up as a defect/deficiency?

I have been writing it up as a deficiency but curious what you all do.

b

Not an Hi, but, if it is a new install and does not meet the new requirements would that not be a defect? If it pre-dated the 4 wire requirement seems like the only thing you could say was that a 3 wire receptacle was in place and not current with todays standard.

Re: Clothes Dryer Receptacle Question

Originally Posted by Jim Port

Not an Hi, but, if it is a new install and does not meet the new requirements would that not be a defect? If it pre-dated the 4 wire requirement seems like the only thing you could say was that a 3 wire receptacle was in place and not current with todays standard.

Re: Clothes Dryer Receptacle Question

I suspect some of the differences is based on the way one reads "new install", as in:
a) *The appliance* was a "new install".
b) *The circuit* was a "new install".

If a) above was found, then that would not be a defect as the circuit was installed like that (presuming that the circuit was installed within the requirements of the exception, and most that I have seen were not).

If b) above was found, then that would be a defect as the circuit was not installed as it should have been.

Just my thinking of why there appears to be confusion in some of the above posts.

Re: Clothes Dryer Receptacle Question

So is the concensus of the BOARD that if a home has 3-wire rather than 4-wire, then we as inspectors should be writing that up as a defect/deficiency?

I have been writing it up as a deficiency but curious what you all do.

b

I don't write it up as a defect..... if I did I'd have to write up every other code change between the time the house was built and today. Why just pick one to harp on?

I do, however, point out the dryer plug configuration to the buyer and make them aware that theirs may not fit so plan accordingly. There's nothing worse than trying to plug in the dryer on moving day only to realize it doesn't fit.

I'll also mention the benefits of a newer 4-wire setup and explain it, if anyone wants to listen.... usually they don't. Basically, I'll talk and explain all day if someone wants to listen and document defects in the report.

Re: Clothes Dryer Receptacle Question

At some point, ( when ? ), it was determined that the neutral wire and the ground wire should remain isolated from each other after the bonding jumper point to avoid circling fault paths. A potential problem, but not a very significant one. The unwrittem problem w/ 3 or 4 wire dryer outlets is how they are connected. If a 4 wire circuit / cable ends up w/ the neutral and ground connected together to supply a 3 wire outlet, the circling fault path is created. If the ground wire is just abandoned / left alone and the 3 wire outlet connected to the neutral, no circling fault path. Too many words for a limited potential problem, so the band width is not even wasted.

Re: Clothes Dryer Receptacle Question

Last month went back to a house (rental) that I had changed the service on in 2005 or so, tenants had replaced the dryer receptacle I installed to a 3-wire. Sad thing is that converting a range or dryer to 4-wire is EZ, but is EZ to do wrong too.....
This house has the orig. wiring from when it was built in the 30's, 2 -15A circuits do most of the house, the orig dryer feed was shared w/ a electric range so it was removed & the dryer circuit refed, range is gas.

Made me mad they changed it, but it was inspected w/ a 4-wire, & have no control over it since.

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